The Collaborative International Dictionary of English v.0.48:

Dovetail \Dove"tail`\, n. (Carp.)
   A flaring tenon, or tongue (shaped like a bird's tail
   spread), and a mortise, or socket, into which it fits
   tightly, making an interlocking joint between two pieces
   which resists pulling a part in all directions except one.
   [1913 Webster]

   Dovetail molding (Arch.), a molding of any convex section
      arranged in a sort of zigzag, like a series of dovetails.


   Dovetail saw (Carp.), a saw used in dovetailing.
      [1913 Webster]